The principal overall objectives are to elucidate the ecology of the dengue viruses and related arboviruses in Malaysia, with special reference to hypothesized jungle cycles; and to establish the importance of such cycles in relation to disease in man. Intensive studies of wild and sentinel primates and jungle mosquitoes in isolated primary forest will be conducted to obtain conclusive evidence that dengue is a zoonosis, and to establish what vertebrate and mosquito species are principally involved. A variety of tested collecting methods will be employed including a trap-release-retrap program of wild monkeys and the use of monkey-baited mosquito traps. Laboratory studies will include isolation, characterization, and identification of viruses and detailed serology utilizing mice and cell cultures in standard procedures.